Antimicrobial coatings can be used in a variety of space life support and commercial applications where control of microbial growth is of particular concern.
High temperature cure, hydrophilic (optionally antimicrobial) coatings that rely upon an inorganic compound, such as silica, to provide hydrophilic characteristics to the coating, are known.
U.S. Pat. No. 5,562,949 to Steele et al. discloses an optionally antimicrobial, hydrophilic, high temperature cure coating composition that contains from about 10% to about 20 wt. % of an inorganic compound (e.g., silica, calc ium silicate or mixtures thereof). This reference teaches that complete curing of the coating occurs at temperatures up to and including 260.degree. C.
U.S. Pat. No. 5,305,827 to Steele et al. discloses an antimicrobial, hydrophilic coating that comprises an adhesive agent (e.g., potassium silicate); an insolubilizer (e.g., zinc oxide); an inorganic compound (e.g., silica, calcium silicate, and mixtures thereof); and from about 0.1 wt. % to about 1.0 wt. % of silver oxide. The coating of U.S. Pat. No. '827 is cured at a temperature of 5000.degree. F. (260.degree. C.) either sequentially or very slowly over a period of from 1 to 6 hours (see Col. 5, lines 62-65 of U.S. Pat. No. '827).
U.S. Pat. No. 5,264,250 to Steele et al. discloses a method for coating heat transfer surfaces of a condensing heat exchanger with the above-referenced antimicrobial, hydrophilic coating. Again, this reference teaches a cure temperature of 500.degree. F. (260.degree. C.).
As will be readily evident to those skilled in the art, such high temperature cure coatings are not applicable to, nor can such coatings be applied in close proximity to, heat sensitive materials. Further, the need to cure coatings at high temperatures complicates the coating process by increasing the processing time and the complexity of the equipment associated therewith.
It is therefore an object of the present invention to provide a room temperature cure, antimicrobial coating.
It is a more particular object to provide a room temperature cure, antimicrobial coating that demonstrates a balance of properties including low dissolution and good cohesion and adhesion.
It is yet a more particular object to provide a room temperature cure, antimicrobial coating that demonstrates a greater zone of microbial inhibition, greater cohesion and a greater degree of adhesion to target surfaces when compared to high temperature cure, antimicrobial, hydrophilic coatings.
It is a further object to provide an air handling or water processing system or subsystem having chronically moist or wet surfaces that have been coated with such a room temperature cure, antimicrobial coating.